1. Field of the Invention
This invention relates to rocket and jet engines. More particularly, it is a reaction engine which is convertible interchangeably and variably in flight between air-breathing and on-board-oxidizer modes of operation by use of reciprocative actuation of a double-acting compressor piston by a double-acting power piston directly through a reciprocative power shaft connecting them to compress air for air-breathing mode to a thruster with flash-boiler-steam injection of water into a double-ended power cylinder and separate flash-boiler-steam injection of water into a thruster as a cooling propellant to utilize heat of stoichiometric combustion completely for compression by a compressor for variable or complete air-breathing mode and for selectively variable or complete air-breathing and rocket thrust modes with the same thruster for both modes.
2. Description of Related Art.
It has been known since the beginning of the Rocket Era that there would be no need for the massive costs, danger and confining utility of blast-off rocketry if an air-breathing jet engine could provide the efficiency and stratospheric thrust velocity of a liquid rocket engine and if it were convertible interchangeably in flight between jet and rocket modes of operation. Such an engine would make space flight less expensive than present long-distance commercial air flight. More speed per fuel consumption could be achieved with decreasing resistance at stratospheric and space altitudes. Short-distance air flight also would be far less expensive.
That is the objective and nature of this invention. It solves problems of present air-breathing and rocket reaction engines to make possible a rocketjet engine that combines the best features and performs the best functions of each synergistically. With different structure and different working relationships of parts, it is a highly versatile reaction engine with far greater effectiveness and economy than present rocket engines, space systems, jet engines, propeller engines and helicopter systems. The effects can be similar for high-speed marine transportation and water propulsion systems.
Turbojet engines require airflow-overrun cooling for maintaining material integrity of turbine blades and associated engine parts. Excess air for the overrun cooling is compressed to full combustion-supportive pressure along with air utilized to achieve complete combustion even though only minimal mass augmentation is derived from it as an added thrust benefit. Decrease of combustion heat decreases combustion pressure by the same two-thirds proportion, leaving only one-third as much pressure to cause exhaust velocity for achieving thrust. This occurs upstream from venturi "squirting" of a mixture of combustion gases and overrun air. It is upstream also from velocity-retarding turbine power-take-off for operating a turbine compressor. Mass-flow is increased by the excess air but with the high penalty of decreased pressure from the cooling required. Because the cooling air does not add expansion pressure independently of combustion pressure, mixture of combustion gases with the cooling air decreases exhaust velocity as a result of both heat reduction and inertial resistance more than though the mixture occurred downstream from a thruster venturi for mass augmentation. As a result of these factors, exhaust velocity is approximately one-third of the velocity of liquid rocket engines that an air-breathing jet engine could achieve without airflow overrun cooling and without obstruction by turbine blades. Exhaust velocity and cooling of a turbine engine in rocket mode would be inadequate for convertibility between rocket and jet modes of operation. Consequently, turbojet engines are incapable of providing sufficient propellant efficiency and exhaust velocity in the atmosphere and in the stratosphere for achieving earth-orbital or earth-escape velocity either in combination with a rocket engine or separately.
Solid rocket engines and ram jet engines separately or together also are incapable of providing sufficient atmospheric thrust for economically-feasible space travel. The technical reasons are different. Solid rocket engines contain materials that "host" solid fuel, that cool thruster housing and that, therefore, decrease exhaust temperature, pressure and velocity to approximately two-thirds that of liquid rocket engines. In addition, solid rocket engines are heavy in proportion to their achievable thrust because propellant is carried in a thruster that must be heavily constructed to contain combustion pressure and heat. Propellant host material also adds weight to solid rocket engines.
Ram-jet-engine air-scoop resistance is, in effect, vehicle resistance. Vehicle resistance resulting from ram pressurization increases propulsive power and propellant required proportionately. Fuel is injected at a sufficient rate greater than stoichiometric requirements to achieve propulsive combustion at a high flow rate of ram-compressed air. Initial ram-pressurization speed must be provided by turbojet, solid rocket or liquid rocket engine system. It is a thrust-augmentation engine which must be separated from a host engine after providing a stage of thrust assistance for most applications. But it provides this assistance at high penalties of fuel weight from high fuel consumption and from vehicle resistance. To the extent that air or other oxidizer can be pressurized sufficiently without it, ram-jet engines and partial ram pressurization in any type of engine should be avoided to the fullest extent possible.
In liquid rocket engines, cooling losses are largely avoided because there are no turbine blades or other moving machinery to cool for maintaining material integrity. For this reason, liquid-rocket exhaust velocity is approximately three times that of turbojet engines. However, rocket engines must propel themselves or be propelled sufficiently far into the stratosphere with the aid of other engine systems to achieve space flight.
Various combinations of ram-jet, turbojet, solid-rocket and liquid-rocket engines may be devised to achieve space flight with a space plane as currently being attempted by U.S. sponsorship through NASA and by sponsorships of other governments. However, the costs are astronomically exorbitant and the effects are infinitesimal in comparison to what can be achieved with this invention.
Prior U.S. Pat. No. 3,541,795 issued to the same primary inventor, Daniel E. Nelson, on Nov. 24, 1970 described an earlier version of a rocketjet engine. Unlike this invention, however, it did not have a means for preventing pistons from hitting ends of cylinders in reciprocative travel. There was no rotational power-take-off for operating peripheral equipment or for operating an optional propeller for low-altitude atmospheric thrust augmentation. It was limited to a regenerative chamber outside of a combustion cylinder. Nor did it provide flash-boiler-steam injection of water as a propellant and other significant features of this invention.
Similar principles in a totally different mechanical system using special turbine components were described in U.S. Pat. No. 3,308,626 for a convertible turbine-ram-rocket engine issued to the same inventor, Daniel E. Nelson, on Mar. 14, 1967.
Similar mechanical components in totally different products with different working relationships of parts are explained in the following additional patents issued to the same inventor.
______________________________________ 3,57.0.,463 Nelson Regenerative Piston (Shaft) Engine 3,685,294 Nelson Hot Gas Pumps and Thrusters 3,916,7.0.2 Nelson Double Roller Cam Drive 3,999,4.0.2 Nelson Regenerative Refrigerator ______________________________________
No anticipating prior art has been found and none is believed to exist.